Corrugated catalytic cigarette paper and cigarettes comprising the same

ABSTRACT

A catalyst-modified corrugated cigarette paper wrapper comprises a fibrous web, an optional web-filler material supported by the web, and catalyst particles supported by the web and/or the web-filler material. In cigarettes comprising the catalyst-modified corrugated cigarette paper, the corrugations define axially-extending channels that can run the length of a tobacco rod. The corrugations can increase the catalytic efficiency of catalyst particles that are incorporated within the catalyst-modified corrugated cigarette paper wrapper.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119(e) to U.S.provisional Application No. 60/754,897, filed on Dec. 30, 2005, theentire content of which is incorporated herein by reference.

BACKGROUND

In the description that follows reference is made to certain structuresand methods, however, such references should not necessarily beconstrued as an admission that these structures and methods qualify asprior art under the applicable statutory provisions. Applicants reservethe right to demonstrate that any of the referenced subject matter doesnot constitute prior art.

Cigarettes produce both mainstream smoke during a puff and sidestreamsmoke during static burning. Constituents of both mainstream smoke andsidestream smoke are carbon monoxide (CO) and nitric oxide (NO). Thereis an interest in reducing the concentration of carbon monoxide andnitric oxide in mainstream and sidestream smoke.

SUMMARY

A cigarette comprises a tobacco rod wrapped in a cigarette wrapper,wherein the cigarette wrapper comprises a catalyst-modified corrugatedcigarette paper wrapper having a fibrous web, an optional web-fillermaterial supported by the web, and catalyst particles supported by theweb and/or the web-filler material. Catalyst-modified corrugatedcigarette paper comprises a fibrous web, an optional web-filler materialsupported by the web, and catalyst particles supported by the web and/orthe web-filler material.

The catalyst-modified corrugated cigarette paper wrapper defines aplurality of channels that run axially along the length of thecigarette. The corrugations are preferably sized such that theirspacing, peak to valley, is less than their height. A preferredcatalyst-modified corrugated cigarette paper wrapper is a compositewrapper further comprising a non-corrugated paper wrapper wrapped aroundthe catalyst-modified corrugated paper wrapper. The non-corrugated outerwrapper can be substantially free of catalyst particles or can comprisecatalyst particles on an inner surface thereof. A further preferredcomposite wrapper comprises a gas permeable inner wrapper.

The catalyst particles (e.g., nanoscale catalyst particles) can beincorporated in the catalyst-modified corrugated cigarette paper wrapperin an amount effective to reduce the concentration in mainstream smokeof carbon monoxide and/or nitric oxide during smoking of a cigarettecomprising the wrapper.

Preferred catalyst particles, which can be coated on an exposed surfaceof the paper or supported within the fibrous web of the paper (e.g.,supported on web-filler material such as calcium carbonate), comprise atransition metal oxide and/or a transition metal hydroxide such asoxides and/or hydroxides of iron. Preferred catalyst-modified corrugatedcigarette paper has a permeability of between about 5 and 80 Corestaunits.

A method of making a cigarette comprising a catalyst-modified corrugatedcigarette paper wrapper comprises (i) optionally supporting catalystparticles on a web-filler material to form a catalyst-modifiedweb-filler, (ii) incorporating catalyst particles and/orcatalyst-modified web-filler in cigarette paper to form catalyticcigarette paper, (iii) forming corrugations in cigarette paper to form acorrugated cigarette paper, (iv) providing cut filler comprising tobaccoto a cigarette making machine, and (v) placing the corrugated cigarettepaper around the cut filler to form a tobacco rod portion of thecigarette. Optionally, a non-corrugated second wrapper can be placedaround the catalyst-modified corrugated cigarette paper wrapper. Thenon-corrugated second wrapper can be free of catalyst particles or canhave catalyst particles incorporated on an inner surface thereof. In afurther embodiment, a gas permeable inner wrapper can be formed aroundthe cut filler prior to forming the catalyst-modified corrugatedcigarette paper wrapper around the cut filler.

A method of manufacturing catalyst-modified corrugated cigarette papercomprises (i) forming cigarette paper, (ii) forming corrugations in thecigarette paper, and (iii) incorporating catalyst particles in thecigarette paper. The steps of forming corrugations in the paper andincorporating catalyst particles in the paper can be performed in eitherorder.

A first preferred method of manufacturing catalyst-modified corrugatedcigarette paper comprises supplying cellulosic material and catalystparticles to a head box in a forming section of a papermaking machine,the catalyst particles comprising unsupported catalyst particles and/orcatalyst modified web-filler; depositing an aqueous slurry including thecellulosic material and the catalyst particles onto the forming sectionof the papermaking machine to form a base web with the catalystparticles distributed therein; and removing water from the base web soas to form a sheet of catalytic paper.

A second preferred method of manufacturing catalyst-modified corrugatedcigarette paper comprises supplying cellulosic material to a head box ina forming section of a papermaking machine; depositing an aqueous slurryincluding the cellulosic material onto the forming section of thepapermaking machine to form a base web; distributing catalyst particleson the base web; and removing water from the base web so as to form asheet paper.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a cigarette comprising acatalyst-modified corrugated cigarette paper wrapper according to oneembodiment.

FIG. 2(a) is an axial view of the cigarette of FIG. 1, and FIG. 2(b)shows a magnified view.

FIG. 3 shows a cigarette comprising a catalyst-modified corrugatedcigarette paper wrapper and a second outer wrapper.

FIG. 4(a) shows an axial view of the cigarette of FIG. 3, and FIG. 4(b)shows a magnified view.

FIG. 5 shows an axial view of a cigarette comprising a catalyst-modifiedcorrugated cigarette paper wrapper according to a further embodiment.

FIG. 6 is a schematic illustration of a papermaking machine for making acatalytic cigarette paper.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A catalyst-modified corrugated cigarette paper wrapper comprises afibrous web, an optional web-filler material supported by the web, andcatalyst particles supported by the web and/or the web-filler material.Catalyst-modified corrugated cigarette paper can be used to manufacturea cigarette and is typically consumed during smoking of the cigarette.In cigarettes comprising a catalyst-modified corrugated paper wrapper,the concentration in mainstream and sidestream smoke of carbon monoxideand/or nitric oxide can be reduced.

In cigarettes comprising catalyst-modified corrugated cigarette paperwrappers, the catalyst particles can promote the conversion of carbonmonoxide (CO) to carbon dioxide (CO₂) via catalysis and/or oxidationmechanisms. As an example, the catalyst particles can promote theoxidation of carbon monoxide by a gaseous source of oxygen according tothe reaction MO_(x)+2CO+O₂=MO_(x)+2CO₂, where MO_(x) represents atransition metal oxide catalyst, or a mixture of transition metal oxidecatalysts (M=a transition metal such as Ti, V, Cr, Mn, Fe, Co, Ni, Cu,Zn, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Ce, Ta, W, Re, Os, Ir, Pt or Au), andx is a positive real number. Further, it is believed that subsequent tothe catalytic reaction, the catalyst particles can oxidize carbonmonoxide by donating an oxygen atom to a carbon monoxide moleculeaccording to the equation MO_(x)+CO=MO_(x−1)+CO₂. The oxidation of COcan proceed in the presence or absence of a gaseous source of oxygen. Inaddition to converting CO to CO₂, the catalyst particles can promote theconversion of nitric oxide to nitrogen via catalysis and/or reductionmechanisms.

The catalyst particles can comprise transition metal oxides and/ortransition metal hydroxides. Exemplary catalyst particles comprise ironoxide, iron hydroxide and/or iron oxyhydroxide. Preferred catalystparticles include α-Fe₂O₃, γ-Fe₂O₃, FeOOH, and mixtures thereof. Forinstance, MACH I, Inc., King of Prussia, PA markets nanoscale particlesunder the trade names NANOCAT® Superfine Iron Oxide (SFIO) and NANOCAT®Magnetic Iron Oxide. The NANOCAT® Superfine Iron Oxide comprisesamorphous ferric oxide (e.g., Fe₂O₃) in the form of a free-flowingpowder with an average particle size of about 3 nm, a specific surfacearea of about 250 m²/g, and a bulk density of about 0.05 g/cm³. TheSuperfine Iron Oxide is synthesized by a vapor-phase process, whichrenders it substantially free of impurities that may be present inconventional catalysts, and is suitable for use in food, drugs, andcosmetics. The NANOCAT® Magnetic Iron Oxide is a free-flowing powderwith a particle size of about 25 nm and a surface area of about 40 m²/g.The catalyst particles can have a shape that is spherical, cubical,and/or acicular.

Other exemplary catalyst particles comprise ceria-based catalystparticles. Ceria-based catalyst particles can oxidize CO at near ambient(i.e., room) temperatures. Suitable ceria-based catalyst particles aredisclosed in commonly-owned U.S. Pat. No. 6,857,431, the entire contentof which is herein incorporated by reference. Still further exemplarycatalyst particles comprise doped metal oxides such as yttria doped withzirconium, manganese oxide doped with palladium, or mixtures of metaloxides, doped metal oxides, etc., which are disclosed in commonly-ownedU.S. Patent Publication No. 2003/0131859, the entire content of which isherein incorporated by reference.

In a preferred embodiment, the catalyst particles can comprise nanoscaleparticles. By “nanoscale” is meant that the catalyst particles have anaverage particle size of less than about 500 nanometers, preferably lessthan about 100 nanometers, most preferably less than about 10nanometers. A bulk density of the catalyst particles is preferably lessthan about 0.3 g/cm³, more preferably less than 0.1 g/cm³. The Brunauer,Emmett, and Teller (BET) surface area of preferred catalyst particles isgreater than about 10 m²/g (e.g., greater than 50,100 or 200 m²/g).

The ratio, in weight percent, of web-filler material to catalystparticles can be any suitable ratio ranging from 0% to 99%. Theweb-filler material, if provided, can include an oxide, carbonate orhydroxide of a Group II, Group III or Group IV metal, or the web-fillermaterial can be selected from the group consisting of CaCO₃, TiO₂, SiO₂,Al₂O₃, MgCO₃, MgO, and/or Mg(OH)₂. A preferred average particle size ofthe web-filler material is from about 0.1 to 10 micrometers, morepreferably less than about 2 micrometers.

A catalyst-modified corrugated cigarette paper wrapper can increase thefirmness and rigidity of a cigarette. Furthermore, a catalyst-modifiedcorrugated cigarette paper wrapper can increase the catalytic efficiencyof catalyst particles incorporated in the wrapper.

An embodiment of a cigarette having a catalyst-modified corrugatedcigarette paper wrapper is shown in FIG. 1. Cigarette 100 has a tobaccorod portion 110 and a filtering tip portion 120. Optionally, embodimentsof the cigarette 100 can be practiced without a filtering tip. Thetobacco rod portion 110 comprises a column of tobacco 112 that iswrapped with a cigarette paper wrapper 130. The cigarette paper wrapper130 preferably comprises a thin, flexible corrugated layer 140.

An axial view of cigarette 100 is shown in FIG. 2(a). As shown in theexpanded view in FIG. 2(b), the catalyst-modified corrugated cigarettepaper wrapper 140 includes a web 142 of fibrous cellulosic material inwhich is preferably dispersed particles of web-filler material 144 suchas calcium carbonate (CaCO₃). Incorporated in the catalyst-modifiedcorrugated paper wrapper 140 are catalyst particles 146. The catalystparticles 146 can be supported directly on the paper web 142, or in analternate embodiment, the catalyst particles can be supported onparticles of the web-filler material 144. The terms “incorporated in”means that the catalyst particles can be surrounded by the matrix ofcellulosic material (i.e., embedded between fibers of cellulosicmaterial), or coated on at least one exposed surface of the paper web.

The corrugations provide a plurality of channels 150 adjacent to thetobacco column that run axially along the length of the cigarette. Thus,smoke (e.g., mainstream and/or sidestream smoke) flowing down thechannels can pass over a relatively large area of the corrugated paperwrapper, and when compared to non-corrugated wrappers, the smoke can bein contact with a larger volume of catalyst particles that areincorporated in the wrapper.

In practice, the gas permeability (i.e., porosity) of cigarette papercan be controlled using the web-filler material 144. The permeability ismeasured in units of Coresta, which is defined as the volume of air,measured in cubic centimeters, that passes through one square centimeterof material in one minute at a pressure gradient of 1 kilopascal.

The permeability of the catalyst-modified corrugated cigarette paperwrapper is preferably from about 5 Coresta units to about 80 Corestaunits, and more preferably from about 30 to 35 Coresta units. Otherpermeabilities of the wrapper can be selected based on the applicationand location of the wrapper. Further, the catalyst-modified corrugatedcigarette paper wrapper can have a basis weight of from about 18 g/m² to60 g/m², more preferably from about 30 g/m² to about 45 g/m². However,any suitable basis weight for the corrugated wrapper can be selected.The paper wrapper can have a thickness of from about 15 to 100micrometers, more preferably from 20 to 50 micrometers.

Optionally, the catalyst-modified corrugated cigarette paper wrapper cancomprise a multi-layer (e.g., composite) wrapper. Additional layers in amultilayer wrapper can be from 0.1 to 10 times the permeability of thefirst layer, and can have a thickness of from 0.1 to 2 times thethickness of the first layer. In embodiments where a composite wrapperis provided (e.g., a conventional wrapper formed around acatalyst-modified corrugated cigarette paper wrapper), both thepermeability and the thickness of the inner layer and the outer layercan be selected to achieve a desired total air permeability and totalthickness for the cigarette.

A preferred cigarette comprises a composite catalyst-modified corrugatedcigarette paper wrapper. An embodiment of a cigarette having a compositecigarette paper wrapper is shown in FIGS. 3 and 4(a)-(b). Cigarette 300includes a tobacco rod portion 310 including a tobacco column 312 and afiltering tip portion 320. Embodiments of the cigarette 300 can bepracticed without a filtering tip. The tobacco rod portion 310 comprisesa column of tobacco 312 wrapped with a composite cigarette paper wrapper330. The composite cigarette paper wrapper 330 comprises a thin,flexible corrugated layer 340 and an outer layer 345 of sheet materialthat surrounds the catalyst-modified corrugated cigarette paper wrapper340.

An axial view of the cigarette 300 is shown in FIG. 4(a). Inner channels350 are formed between the tobacco column 312 and the catalyst-modifiedcorrugated cigarette paper 340, and outer channels 352 are formedbetween the catalyst-modified corrugated cigarette paper 340 and theouter layer of sheet material 345. As in the previous embodiment,compared to a non-corrugated wrapper, the plurality of channels in thecatalyst-modified corrugated cigarette paper wrapper can increase thecontact area between mainstream and/or sidestream smoke and the catalystparticles incorporated in the wrapper.

Because the addition of catalyst particles can discolor cigarette paper,e.g., a paper wrapper becomes non-white or brown, in a preferredembodiment, an outer wrapper that is a conventional color, e.g., white,can be placed around an inner corrugated wrapper having catalystparticles incorporated therein. The outer wrapper is preferably not acorrugated wrapper and can be free of catalyst particles so as toprovide a smooth outward appearance to the cigarette that is notaffected by any coloration from the catalyst particles. Alternatively,catalyst particles can be incorporated in the outer wrapper. Forexample, catalyst particles can be coated on an inner surface of theouter wrapper in order to minimize discoloration of the outer surface ofthe outer wrapper.

FIG. 4(b) shows an expanded view of the cigarette shown in FIG. 4(a).The catalyst-modified corrugated cigarette paper wrapper 340 includes aweb of fibrous cellulosic material 342 in which is optionally dispersedparticles of web-filler material 344. Catalyst particles 346 areincorporated in the corrugated wrapper 340, and the catalyst particlescan be supported directly on the paper web 342 or on particles ofweb-filler material 344, if provided.

In the embodiment illustrated in FIGS. 3 and 4(a)-(b), the innercorrugated wrapper and the outer wrapper are preferably individualwrappers formed in separate papermaking processes and later wrappedaround a column of tobacco cut filler to from a cigarette tobacco rod.The corrugated inner wrapper, the outer wrapper or both wrappers caninclude catalyst particles (or catalyst-modified web-filler). Inexamples where catalyst particles are incorporated in both wrappers, thecatalyst composition, particle shape, size and loading in each wrappercan be the same or different. Both the inner corrugated wrapper and theouter wrapper can be selected to give a desired performance with respectto cigarette properties, such as puff count, tar, burn rate, and ashappearance. As shown and described, for example, in FIGS. 3 and4(a)-(b), the preferred embodiments of cigarettes and methods of makingcigarettes include a tobacco rod portion of a cigarette with a compositewrapper. A preferred composite wrapper comprises an innercatalyst-modified corrugated cigarette paper wrapper and an outerwrapper that is substantially free of catalyst particles.

A composite catalyst-modified corrugated cigarette paper wrapper canoptionally further comprise an inner layer of sheet material adapted tobe formed between the tobacco column and the corrugated layer. The innerlayer, if provided, is preferably permeable to smoke either by virtue ofa relatively porous structure or by the formation of perforationstherethrough. When an inner layer of sheet material is provided, innerchannels are formed between the inner layer of sheet material and thecatalyst-modified corrugated cigarette paper.

FIG. 5 shows a cigarette comprising a catalyst-modified corrugatedcigarette paper wrapper having a higher density of corrugations than theprevious embodiments illustrated in FIGS. 1-4. In the embodimentillustrated in FIG. 5, the catalyst-modified corrugated cigarette paperwrapper 564 comprises corrugations that bend back upon themselves andform loops, each of which touches the preceding and the following loopof the corrugation near the optional outer layer 566 and again near thetobacco column 502. In this embodiment, the corrugations can be glued orotherwise attached at least at those points where they contact eachother near the outer and inner circumference of the wrapper. Such acorrugated wrapper can be made sufficiently flexible for use withcigarette making machines. By omitting the outer layer 566 of sheetmaterial, the cigarette can have an outward appearance different fromthat of a standard cigarette.

In each of the aforementioned embodiments, it is particularly preferredthat the catalyst-modified corrugated cigarette paper wrapper have athickness that is less than a radius of the tobacco rod (i.e., such thatthe wrapper represents 50% or less of the diameter of a cigarettecomprising the wrapper). It is further preferred that the corrugationsbe uniformly spaced, peak to valley, at a distance less than theirheight, so that a tangent to their sloping portions, assuming a regularsinusoidal waveform, makes an angle of less than about 45° (e.g., lessthan about 40°, 35° or 30°) with respect to a radial axis line of acigarette comprising the wrapper.

The axially extending channels defined by the corrugations in thevarious embodiments may be either opened or closed and, if closed, maybe closed at the mouth end of the cigarette, filter end of thecigarette, or both. If the channels are closed, it may be desirable toperforate the wrapper when dilution is desired. Closing either the innerchannels or the outer channels while leaving the others open can beaccomplished prior to manufacturing the cigarette.

In preferred embodiments, the channels are open. If, for example,flavoring is added to the catalyst-modified corrugated cigarette paper,smoke and air may be drawn along the open channels toward the mouth end.

Catalyst-modified corrugated cigarette paper can be made byincorporating catalyst particles in corrugated cigarette paper. Forexample, a liquid dispersion of catalyst particles can be spray coatedon at least one surface of corrugated paper. Alternatively,catalyst-modified corrugated cigarette paper can be made by formingcorrugations in catalytic cigarette paper. Catalytic paper comprisescatalyst particles that are incorporated in the paper. Preferred methodsof forming catalytic paper are described herein below.

One method of forming the corrugations comprises passing a sheet ofcigarette paper between two grooved or threaded rollers. The depth andpitch of the corrugations in the paper can be controlled by the geometryof the forming rollers and the pressure applied to them. When threadedrollers are used, one such roller preferably has a right-handed threadand the other such roller preferably has a left-handed thread, and theyare rotated in an opposite sense so that the paper can be fed betweenthe two rollers. The number of corrugations can be controlled by varyingthe number of grooves or threads on the forming rollers and may rangefrom about 10 to about 60 per inch. The depth of the corrugations mayrange from about 0.01 to 0.1 inch.

According to preferred methods of forming catalytic cigarette paper, thecatalyst particles can be incorporated into cigarette paper before,during, or after the papermaking/corrugation processes. According to afirst embodiment, the catalyst particles can be incorporated within thefibrous web of the paper by first supporting the catalyst particles onweb-filler material to form a catalyst-modified web-filler and thenincorporating the catalyst-modified web-filler in the paper. In apreferred example, the catalyst-modified corrugated cigarette paper cancomprise CaCO₃ web-filler or other filler material used in cigarettepaper manufacture and nanoscale iron oxide catalyst particles that aresupported on the web-filler material.

A catalyst-modified web-filler can be prepared by forming an aqueousslurry of catalyst particles and web-filler material and drying theslurry. Other techniques for forming a catalyst-modified web-fillerinclude precipitating catalyst particles from a solution onto aweb-filler material, or depositing (e.g., via vapor phase deposition)catalyst particles onto a web-filler material. A catalyst-modified webfiller can be used as all or part of the web-filler material in thepaper-making process.

Advantageously, the web-filler-supported catalyst particles such assupported nanoscale catalyst particles can exhibit a reduced tendency toagglomerate with each other during processing and a reduced tendency toleech out of the catalytic paper during or after cigarette papermanufacture.

According to a second embodiment, the catalyst particles can beincorporated in a cigarette paper by supporting the catalyst particlesdirectly on the cellulosic fibers of the paper web. Catalyst particlescan be coated (e.g., curtain coated), sprayed, or printed on a wet ordry base web. A retention aid can be used to improve the distributionand adhesion of the catalyst particles. In a further example, thecatalyst-modified corrugated cigarette paper wrapper comprises nanoscaleiron oxide particles that are supported directly on the paper web.

The catalyst particles and web-filler material, if provided, can beincorporated in a cigarette paper using conventional papermakingprocesses. Catalyst particles and/or catalyst-modified web filler can besupplied to the papermaking process as an aqueous slurry or as a drypowder to be slurried. For example, an aqueous slurry (“furnish”)including the catalyst particles and cellulosic material can be suppliedto a head box of a forming section of a Fourdrinier papermaking machine.The aqueous slurry can be supplied to the head box by one or moreconduits in fluid communication with a source, such as a storage tank.Optionally, an aqueous slurry containing catalyst particles and anaqueous slurry of cellulosic material without catalyst particles or witha different concentration or type of catalyst particles can be suppliedto separate head boxes.

An exemplary method deposits aqueous slurry from a head box onto aforming section so as to form a base web of cellulosic material. In atypical Fourdrinier machine, the forming section is a Fourdrinier wirearranged as an endless forming wire immediately below the head box. Anopening defined in a lower portion of the head box adjacent to theendless wire permits the aqueous slurry to flow onto the top surface ofthe endless wire to form a wet base web.

Optionally, the aqueous slurry can be deposited onto a pre-formedsupport web that is retained within the paper. For example, a pre-formedsupport web can be transported through the forming section of apapermaking machine and can be a foundation on which the aqueous slurryis deposited. The aqueous slurry dries and the paper sheet (e.g.,finished web) is formed with catalyst-modified web-filler or catalystparticles embedded therein. The support web can be a conventional web,such as a flax support web, or can include a web with an incorporatedcatalytic component. If the support web includes a catalytic component,the incorporated catalytic component can be supported on a web-fillermaterial, or can be directly supported on the support web without aweb-filler material.

After depositing the aqueous slurry onto the forming section, water isremoved from the wet base web, and with additional processing such asfurther drying and pressing, if necessary, forms a sheet of catalyticpaper (e.g., finished web). The catalytic paper can be corrugated in anadditional processing step.

Referring to FIG. 6, a cigarette papermaking machine 600 includes a headbox 602 operatively located at one end of a Fourdrinier wire 604, andsource of feed stock slurry such as a run tank 606 in communication withthe head box 602. The head box 602 can be one typically utilized in thepapermaking industry for laying down cellulosic pulp upon theFourdrinier wire 604. In the usual context, the head box 602 iscommunicated to the run tank 606 through a plurality of conduits. Therun tank 606 receives furnish from a furnish supply 618. Preferably, thefeed stock from the run tank 606 is a refined cellulosic pulp such as arefined flax or a wood pulp commonly practiced in the cigarettepapermaking industry. Preferably, a chalk tank 628 (containing thecatalyst modified filler described above) is communicated with the runtank 606 so as to establish a desired “chalk” level in the slurrysupplied to the head box 602.

The Fourdrinier wire 604 carries the laid slurry pulp (e.g., base web)from the head box 602 along a path in the general direction of arrow Ain FIG. 6, whereupon water is allowed to drain from the pulp through thewire 604 by the influence of gravity and at some locations with theassistance of vacuum boxes 610, 610′, 610″ at various locations alongthe Fourdrinier wire 604. At some point along the Fourdrinier wire 604,sufficient water is removed from the base web to establish what iscommonly referred to as a dry line where the texture of the slurrytransforms from one of a glossy, watery appearance to a surfaceappearance more approximating that of the finished base web (but in awetted condition, e.g., an intermediate web). At and about the dry line,the moisture content of the pulp material is approximately 85 to 90%,which may vary depending upon operating conditions and the like.

Downstream of the dry line, the intermediate web 612 separates from theFourdrinier wire 604 at a couch roll 614. From there, the Fourdrinierwire 604 continues on the return loop of its endless path. Beyond thecouch roll 614, the intermediate web 612 continues on through theremainder of the papermaking system which further dries and presses theintermediate web 612, and surface conditions it to a desired finalmoisture content and texture to form a paper 620 (e.g., finished web).Such drying apparatus is well known in the art of papermaking, and mayinclude drying section 616 including drying felts, vacuum devices,rolls, and/or presses, applied thermal energy, and the like.

The cigarette making machine 600 can optionally include more than onehead box and/or more than one Fourdrinier wire with either separate orcommon furnish supply. The optional second head box 602′, suitablyintegrated with a run-tank and furnish supply, can lay slurry pulp ontothe slurry pulp laid from the first head box 602 and carried alongFourdrinier wire 604. The second and/or additional head box can besupplied with catalyst modified web filler to a desired “chalk” level orcan be free of catalyst modified web-filler, as desired based on thenumber of layers of slurry pulp to be deposited and/or the use of thewrapper formed from the papermaking process.

The optional second Fourdrinier wire 604′, suitably integrated with ahead box 602′ laying slurry pulp on the Fourdrinier wire 604′ anddraining and drying equipment, can form a second intermediate web 612′.The second intermediate web 612′ can be separated from the secondFourdrinier wire 604′ at a second couch roll 214′ and laid on the firstintermediate web 612 from the Fourdrinier wire 604 to be processed intodouble layer paper. Multiple optional Fourdrinier wires can be employedto form multiple layer paper having any desired number of layers, suchas three, four and so forth, up to ten to twelve layers.

A method of manufacturing catalyst-modified corrugated cigarette papercomprises forming cigarette paper, forming corrugations in the cigarettepaper, and incorporating catalyst particles in the cigarette paper. Thestep of forming corrugations in the cigarette paper can precede orfollow the step of incorporating catalyst particles in the cigarettepaper.

A first preferred method of manufacturing catalyst-modified corrugatedcigarette paper comprises supplying cellulosic material and catalystparticles to a head box in a forming section of a papermaking machine,the catalyst particles comprising unsupported catalyst particles and/orcatalyst modified web-filler; depositing an aqueous slurry including thecellulosic material and the catalyst particles onto the forming sectionof the papermaking machine to form a base web with the catalystparticles distributed therein; and removing water from the base web soas to form a sheet of catalytic paper.

A second preferred method of manufacturing catalyst-modified corrugatedcigarette paper comprises supplying cellulosic material to a head box ina forming section of a papermaking machine; depositing an aqueous slurryincluding the cellulosic material onto the forming section of thepapermaking machine to form a base web; distributing catalyst particleson the base web; and removing water from the base web so as to form asheet paper.

The catalyst-modified corrugated cigarette paper can comprise alaminated, bi-layer or multilayer catalytic paper. Examples of bi-layerand multilayer paper are disclosed in commonly-owned U.S. Pat. No.5,143,098, the entire content of which is herein incorporated byreference. In an embodiment of a bi-layer or multilayer catalytic paper,at least one of a first layer and a second layer can include thecatalyst particles described in embodiments herein.

Single layer, bi-layer or multilayer catalyst-modified corrugatedcigarette paper may be made using ordinary paper furnish such as pulpedwood, flax fibers, or any standard cellulosic fiber. Preferably, flaxfibers are used. Different fillers, including different catalyticfillers such as the catalyst modified web-filler described herein, ordifferent fibers may be used for each layer and may be contained indifferent head boxes. For example, a first head box can hold thematerials for a catalytic paper and a second head box can hold thematerials for a conventional paper wrapper.

Additional methods of forming catalyst-modified web-filler material andmethods of incorporating web-filler material and catalyst-modifiedweb-filler material in cigarette paper are disclosed in commonly-ownedU.S. Patent Publication No. 2005/0051185 and U.S. patent applicationSer. No. 10/870,449, the contents of which are hereby incorporated byreference. Additional examples of papermaking processes include themethod for making banded smoking article wrappers disclosed incommonly-owned U.S. Pat. No. 5,342,484, the entire content of which isherein incorporated by reference, and the method for producing paperhaving a plurality of regions of variable basis weight in the crossdirection disclosed in commonly-owned U.S. Pat. Nos. 5,474,095 and5,997,691, the entire contents of which are herein incorporated byreference.

Catalyst-modified corrugated cigarette paper can be used as a wrapperfor conventional cigarettes or non-conventional cigarettes such ascigarettes for electrical smoking systems described in commonly-assignedU.S. Pat. Nos. 6,026,820; 5,988,176; 5,915,387; 5,692,526; 5,692,525;5,666,976; 5,499,636 and 5,388,594 or non-traditional types ofcigarettes having a fuel rod such as are described in commonly-assignedU.S. Pat. No. 5,345,951, the entire contents of which are hereinincorporated by reference.

The catalyst-modified corrugated cigarette paper wrapper is preferablyadapted to surround the cut filler to form a tobacco rod. In addition tocellulose, the wrapper material can comprise hemp, kenaf, esparto grass,rice straw and mixtures thereof. Optional filler materials such asflavor additives and burning additives can be included.

In cigarette manufacture, the tobacco is normally employed in the formof cut filler, i.e., in the form of shreds or strands cut into widthsranging from about 1/10inch to about 1/20inch or even 1/40inch. Thelengths of the strands typically range from between about 0.25 inches toabout 3.0 inches. The cigarettes may further comprise one or moreflavorants or other additives (e.g., burn additives, combustionmodifying agents, coloring agents, binders, etc.).

Any suitable tobacco mixture may be used for the cut filler. Examples ofsuitable types of tobacco materials include flue cured, Burley, Bright,Maryland or Oriental tobaccos, the rare or specialty tobaccos, andblends thereof. The tobacco material can be provided in the form oftobacco lamina, processed tobacco materials such as volume expanded orpuffed tobacco, processed tobacco stems such as cut-rolled or cut-puffedstems, reconstituted tobacco materials, or blends thereof. The tobaccocan also include tobacco substitutes.

A method of making a cigarette comprising a catalyst-modified corrugatedcigarette paper wrapper comprises (i) optionally supporting catalystparticles on a web-filler material to form a catalyst-modifiedweb-filler, (ii) incorporating catalyst particles and/orcatalyst-modified web-filler in cigarette paper to form catalyticcigarette paper, (iii) forming corrugations in cigarette paper to form acorrugated cigarette paper, (iv) providing cut filler comprising tobaccoto a cigarette making machine; and (v) placing the corrugated cigarettepaper around the cut filler to form a tobacco rod portion of thecigarette.

During the smoking of a cigarette, oxygen diffuses into the cigarettethrough the lit end and through the paper wrapper, and CO and NO inmainstream smoke flow axially toward the filter end and radially out ofthe cigarette through the paper wrapper. After a typical 2-second puff,CO and NO are concentrated in the periphery of the cigarette, i.e.,proximate to the cigarette wrapper, in front of the burn zone. Theoxygen concentration is high in the same region as high CO and NOconcentrations due to diffusion of O₂ into the cigarette. Airflow intothe tobacco rod is largest near the burn zone at the periphery of thecigarette and is approximately proportional to the gradient oftemperature, e.g., larger airflow is associated with higher temperaturegradients.

In a typical cigarette, the temperature varies from about 850-900° C.near the periphery of the cigarette at the burn zone to about 300° C.near the center of the cigarette. The temperature drops further to nearambient temperature at the filter end. The temperature gradient at thelit end is very large and within a few of mm in the axial direction ofthe burn zone, the temperature drops from about 900° C. to about 200° C.Further information on airflow patterns, the formation of constituentsin cigarettes during smoking and smoke formation and delivery can befound in Richard R. Baker, “Mechanism of Smoke Formation and Delivery”,Recent Advances in Tobacco Science, vol. 6, pp. 184-224, (1980) andRichard R. Baker, “Variation of the Gas Formation Regions within aCigarette Combustion Coal during the Smoking Cycle”, Beiträge zurTabakforschung International, vol. 11, no. 1, pp. 1-17, (1981), thecontents of both are incorporated herein by reference.

The loading (e.g., amount), type (e.g., composition, size, shape, etc.)and distribution (e.g., homogeneous or heterogeneous) of catalystparticles in the catalyst-modified corrugated cigarette paper wrappercan be selected as a function of the temperature and airflowcharacteristics exhibited in a burning cigarette in order to adjust,i.e., increase, decrease, minimize or maximize, the conversion rate ofCO to CO₂ and/or the conversion rate of NO to N₂.

The catalyst-modified corrugated cigarette paper wrapper can compriseone or more different kinds of catalyst particles. Low temperature andeven room temperature catalysts can extend the effective region of thereaction zone for CO to C0 ₂ and/or NO to N₂ conversion to any desiredlength along the cigarette.

Catalyst-modified corrugated cigarette paper wrappers can be selected tooperate in a given temperature range or in a plurality of temperatureranges, and the wrapper can be manufactured such that certain catalystparticles are incorporated into those portions of the wrapper that arepredicted to coincide with the appropriate temperature for operation ofthe catalyst. Methods for selectively incorporating catalyst particlesin different regions of a cigarette paper web and for incorporatingdifferent catalyst particles in a cigarette paper web are disclosed inco-pending, commonly-owned U.S. Patent Publication No. 2005/0051185, thecontent of which is hereby incorporated by reference.

Although the catalyst is described as having an operating temperature,the terminology operating temperature refers to the preferredtemperature for conversion of CO to C0 ₂ and/or NO to N₂. The catalystmay convert CO and/or NO outside the described temperature range, butthe conversion rate may be affected.

In any of the examples described herein, the catalyst particles can bedistributed homogeneously or non-homogeneously within acatalyst-modified corrugated cigarette paper wrapper.

In a preferred embodiment, the catalyst particles are incorporated inthe catalyst paper in an amount effective to convert at least 25% ofcarbon monoxide to carbon dioxide and at least 25% of nitric oxide tonitrogen at a temperature of less than 400° C. More preferably, thecatalyst particles can convert at least 50% of carbon monoxide and atleast 50% of nitric oxide at a temperature of less than 400° C.

Any of the wrappers, cigarettes or methods described herein can includeadditional additives conventionally used in wrappers for cigarettes.These additives can include, for example, additives to control theappearance, e.g., color, of the wrapper, additives to control the burnrate of the wrapper, and/or additives to result in a desired ashappearance.

The catalyst-modified corrugated cigarette paper wrapper can beeffective to (1) reduce the concentration in mainstream smoke and/orsidestream smoke of carbon monoxide and/or nitric oxide; (2) decreaseparticle entrainment in mainstream smoke because the catalyst particlesare embedded in or adhered to the wrapper and/or web-filler; (3)increase the catalytic, oxidative and/or reduction efficiency of thecatalyst particles; and/or (4) increase the mechanical integrity of thewrapper.

The terminology “mainstream” smoke refers to the mixture of gases andparticles passing down a tobacco rod and issuing through the filter end,i.e., the amount of smoke issuing or drawn from the mouth end of acigarette during smoking of the cigarette. Mainstream smoke containssmoke drawn in through both the lighted region and through the cigarettepaper wrapper. “Sidestream” smoke is the smoke given off by a cigarettebetween puffs (i.e., during static burning).

The terms “comprises” and “comprising” as used herein are taken tospecify the presence of stated features, steps, or components; but theuse of these terms does not preclude the presence or addition of one ormore other features, steps, components, or groups thereof.

All of the above-mentioned references are herein incorporated byreference in their entirety to the same extent as if each individualreference was specifically and individually indicated to be incorporatedherein by reference in its entirety.

While the invention has been described with reference to preferredembodiments, it is to be understood that variations and modificationsmay be resorted to as will be apparent to those skilled in the art. Suchvariations and modifications are to be considered within the purview andscope of the invention as defined by the claims appended hereto.

1. A cigarette comprising: a tobacco rod wrapped in a cigarette wrapper,wherein the cigarette wrapper comprises a catalyst-modified corrugatedcigarette paper wrapper comprises a fibrous web, an optional web-fillermaterial supported by the fibrous web, and catalyst particles supportedby the fibrous web and/or the web-filler material.
 2. The cigarette ofclaim 1, wherein the catalyst-modified corrugated cigarette paperwrapper comprises a plurality of channels that run axially along thelength of the cigarette; and/or is formed around a gas permeable innerwrapper.
 3. The cigarette of claim 1, wherein the catalyst-modifiedcorrugated cigarette paper wrapper is wrapped by a non-corrugated paperwrapper together forming a composite wrapper.
 4. The cigarette of claim3, wherein the non-corrugated paper wrapper is substantially free ofcatalyst particles; or incorporates catalyst particles on an innersurface of the non-corrugated paper wrapper in an amount effective forreducing the concentration of carbon monoxide and/or nitric oxide inmainstream smoke during smoking of the cigarette.
 5. The cigarette ofclaim 1, wherein the catalyst particles have an average particle size ofless than about 500 nanometer; and/or comprise a transition metal oxide,a transition metal hydroxide, and/or a transition metal oxyhydroxide. 6.A catalyst-modified corrugated cigarette paper comprising: a fibrousweb; an optional web-filler material supported by the fibrous web; andcatalyst particles supported by the fibrous web and/or the web-fillermaterial.
 7. The catalyst-modified corrugated cigarette paper of claim6, wherein the catalyst particles are coated on an exposed surface ofthe catalyst-modified corrugated cigarette paper; and/or are supportedwithin the fibrous web of the catalyst-modified corrugated cigarettepaper.
 8. The catalyst-modified corrugated cigarette paper of claim 6,wherein the catalyst particles have an average particle size of lessthan about 500 nanometers; or less than about 50 nanometers.
 9. Thecatalyst-modified corrugated cigarette paper of claim 6, wherein thecatalyst particles comprise a transition metal oxide, a transition metalhydroxide, a transition metal oxyhydroxide, iron oxide, and/or ironhydroxide.
 10. The catalyst-modified corrugated cigarette paper of claim6, wherein the web filler material is not optional and comprises calciumcarbonate.
 11. The catalyst-modified corrugated cigarette paper of claim6 having corrugations that are uniformly spaced at a distance less thantheir height, from peak to valley.
 12. The catalyst-modified corrugatedcigarette paper of claim 6, wherein the paper has a permeability ofbetween about 5 and 80 Coresta units.
 13. A method of making a cigarettecontaining a catalyst-modified corrugated cigarette paper wrapper, themethod comprising: (i) optionally supporting catalyst particles on aweb-filler material to form a catalyst-modified web-filler; (ii)incorporating catalyst particles and/or catalyst-modified web-filler inthe cigarette paper to form a catalytic cigarette paper; (iii) formingcorrugations in the cigarette paper to form a corrugated cigarettepaper; (iv) providing a cut filler comprising tobacco to acigarette-making machine; and (v) placing the corrugated cigarette paperaround the cut filler to form a tobacco rod portion of the cigarette.14. The method of claim 13, wherein the corrugated cigarette paper is afirst wrapper and the method further comprises (vi) placing anon-corrugated second wrapper around the first wrapper; or thecorrugated cigarette paper is a second wrapper and the method furthercomprises (vi) placing a first gas permeable wrapper around the cutfiller prior to step (v).
 15. The method of claim 14, wherein the secondwrapper is free of catalyst particles; or incorporates catalystparticles on an inner surface of the second wrapper.
 16. The method ofclaim 13, wherein the catalyst particles comprise nanoscale particles.17. A method of manufacturing catalyst-modified corrugated cigarettepaper, the method comprising: (i) forming cigarette paper; (ii) formingcorrugations in the cigarette paper; and (iii) incorporating catalystparticles with the cigarette paper.
 18. The method of claim 17, whereinstep (ii) precedes step (iii); or step (iii) precedes step (ii).
 19. Themethod of claim 17, wherein the incorporating comprises spraying orprinting the catalyst particles on the cigarette paper.
 20. The methodof claim 17, wherein the steps of forming cigarette paper andincorporating catalyst particles in the cigarette paper comprise:supplying cellulosic material and catalyst particles to a head box in aforming section of a papermaking machine, the catalyst particlescomprising unsupported catalyst particles and/or catalyst modifiedweb-filler; depositing an aqueous slurry including the cellulosicmaterial and the catalyst particles onto the forming section of thepaper-making machine to form a base web with the catalyst particlesdistributed therein; and removing water from the base web so as to forma sheet of catalytic paper.
 21. The method of claim 17, wherein thesteps of forming cigarette paper and incorporating catalyst,particles inthe cigarette paper comprise: supplying cellulosic material to a headbox in a forming section of a papermaking machine; depositing an aqueousslurry including the cellulosic material onto the forming section of thepapermaking machine to form a base web; distributing catalyst particleson the base web; and removing water from the base web so as to form asheet of catalyst-modified paper.
 22. The method of claim 17, whereinthe catalyst particles are supported directly on the paper cigarette.